Antistatic system



June 8 1926. 1,588,248 Di G. M cAA ANTISTATIC SYSTEM Filed March 16.192s 2 Sheets-Sheet '1 INVENTOR. Y q W Q4. M Mas Q 2 ATTORNEY.

D. G. MOCAA ANTISTATIC SYSTEM Filed March 16, 1928 2 Sheets-Sheet 2 .mBY mwm 15/2 ATTORNEY.

Patented June 8, 1926.

UNITED STATES 1,588,248 PATENT OFFICE.

A DAVID G. IOCAA, F LANCASTER, PENNSYLVANIA, ASSIGNOB TO THE ELECTRICAP- I PABATUS 00., OF PABKESBURG, PENNSYLVANIA, A CORPORATION OFPENNSYL- AN TISTATIG SYSTEM.

I Application filed larch 16, 1928. Serial No. 625,473.

My invention relates to signaling systems, and more particularly to suchsystems as radio telegraph and other systems in which it is desirable toeliminate or reduce the effects of static, strays, electricalatmospheric disturbances, or other disturbing electrical effects.

My invention resides in a method of andof stronger current for producingthe ultimate signal or effect, with high degree of selectivity andwithout the blurring or"in-- distinctness otherwise resulting fromstatic, atmosphcrics, undesired signals, and like effects.

In its principal and fundamental aspects, my present invention is thesame as that disclosed in my prior application Serial No. 557,911, filedMay 2, 1922.

In accordance with my invention, a fluctuating or alternating current ofdefinite period or frequency represents or is caused to represent thereceived signals, and causes vibration of a mechanical element, as aband, stringer the like, preferably having a natural periodcorresponding with the frequency of the fluctuating or alternatingcurrent, the vibrating element controlling a local current of anysuitable magnitude by co action with a yielding contact structure.

My invention resides in the method and apparatus hereinafter describedand claimed.

For an illustration of some of the various forms my apparatus may take,and for an understandin of my method, reference is to be had to t eaccompanying drawings, in which: Fig. 1 is a diagrammatic view of aradio telegraphic receiving system embodying my invention;

Fig. 2 is 'a view, in side elevation, of a band structure andco-acting'elements utilizable in accordance with my invention.

Fig. 3 is an elevational view of the yield- .50 ing contact structureand associated parts.

Fig. 4 is an elevational view of a modified form of yielding contactstructure.

Fig. 5 is a fragmentary side elevational -view of a modified form ofvibrating element and yielding contact structure.

Fig. 6 is a side elevational view of a modified structure comprising avibrating member and yielding contact structure, both controlled by thesignal-representing curren Y Referring to Fig. 1, A represents anantenna or any equivalent structure for absorbing from a natural medium,or from a conductor system, high or radio frequency'energy representinga signal transmitted from 65 a distant station. The antenna is connectedto ground or counter-capacityEthrough the varlable inductance L andprimary P of an oscillation transformer. vVariation of the inductance Land primary P, or either, serves to tune the antenna path to the high orradio frequency energy; tuning may be facilitated, if suitable-0rdesirable, by a variable condenser C connected in parallel, asindicated, for, relatively long waves, and in series with the antennafor short waves.

Coupled to the primary P is the secondary S of the oscillationtransformer, across whose terminals is connected the tuning condenser C,whereby the circuit S, C may be attuned to the radio frequency received.The received energy may be applied to any suitable detector, as acrystal or other detector, and preferably, as indicated, to a thermionicdetector V, as of the audion type. comprising the anode a, cathode orfilament f and grid or control electrode g, the filament being suppliedwith current from any suitable source, as battery I), through adjustableresistance r. In the circuit of the grid 9 may be included the usualcondenser C shunted by a high leak resistance 1*.

In the anode or plate circuit is the relatively higher otential batteryB and the primary P 0 an audio frequency transformer whose secondary isS, which may be bridged by the condenser G for tuning the circuit S, Cto the frequency of the audio frequency com onent of the current in theanode circuit 0 the tube V.

In circuit with the secondary S are the coils or windings d, d,preferably of relatively higher impedance than the impedance of the coilS surrounding cores e, e disposed, respectively, upon the 105 oppositepoles of the permanently magnetized member or permanent magnet h.Pivoted at *5, upon the bracket or su ort k, is a soft iron armature 7',with who co-acts the biasing spring m engaging with its one the softiron endupon one side of the armature i, and secured or supported at itsother end upon one of the poles n of the cores e. Carried by orsupported on the armature j at its end opposite the spring m is thelight rod 0, which is suitably attached to or merely presses against theband F, which may be of steel or other suitable metal, as bronze, etc.,

or which may be of any suitable non-metallic material, as celluloid,fibre, wood, formica or the like.

The band F may be of any suitable cross section or shape, and may be inthe form of a ribbon or band, a wire or string of circular or othercross section, etc. .The term band is herein used generically to coverall suitable forms, including the ribbon or true band form, vibratorysprings or reeds.

As indicated in Fig. 2, the band F is secured at its one end at q and isheld at its other end in a clamp t having the threaded shank u, uponwhich is threaded the thumb nut '0, turning of which changes the tensionupon the band F to vary or adjust its natural period of vibration, whichis preferably made equal to the period of the current which energizesthe coils d. The band F is stretched over the upper ends of the blocksor members to, forming fulcra, frets or the like for determining withnicety the effective vibration length of the band.

The circuits and structure thus far described will be recognized ascorresponding with similar disclosure in my aforesaidapplication SerialNo. 557,911.

In accordance with my present invention, in lieu of generating orcontrolling the gen eration or production of a current, as in myaforesaid application,-the band F is utilized as one'member of avibrating or vibration relay to control an already existing localcurrent which, under the control of the vibration relay, controls anysuitable signaltranslating means, as a further non-vibrating relay, orthe like.

One of the contacts of the vibration relay is indicated at m, and theco-acting contact may be the band F itself, if suitable or de sirable,or, and preferably, as indicated, the co-acting contact 12 is secured toand in electrical connection with the band F when of metal. As wellunderstood in the art, the contacts :0 and 3 are of platinum, silver orother suitable materials. By preference both contacts m and 3 are ofcoin silver. The contact w is carried by a lover or pendulum a which, asmore clearly indicated in Fig. 3, is provided with a pivot shaft ahaving conical ends bearing in similarly formed recesses in thestationary bearing blocks 72 Secured upon the member .2 is a soft ironarmature 0 with which co-acts the magnet systems d and e whose poles aredisposed on opposite sides of the armature. The magnet system al isenergized by the coil 7 receiving current from the battery or othersource of current 9 the strength of the current traversing winding fbeing adjustable by the variable resistance M. The magnet system 6 is.

energized by the coil 97, which is in circuit with the aforesaid source9 contacts at and y, the winding 7' and adjustable resistance is. Thewinding 71 is shunted by an adjustable resistance m and the relaycontacts at and y are shunted by the condenser C and resistance 1,connected in series with each other, for reducing sparkin and forpreventing delay of ru ture o circuit at the contacts 02, y, as welunderstood in relay practice. The winding j excites the magnet system mwith which co-acts the armature 0 pivoted at p, and biased for movementaway from the poles of the system n by the spring 9 The armature pcarries the contact 3 which co-acts with the adjustable stationarycontact 25 controlling the circuit of the signal-translating instrumentT, or sounder, tape recorder or the like, the circuit being energized bythe battery or source of current a Or T may represent any suitabletelegraphic transmitting relay or automatically operated key, forcontrolling transmission of the received signals over a land line, orthe structure T may control a radio transmitting apparatus.

Assuming the distant transmitting station to be transmitting signalsrepresented by short wave trains, or trains of decadent oscillations asin spark transmitters, there will appear in the circuit of the coils d afluctuating or alternating current whose frequency corresponds to thewave train frequency of the distant transmitting station. The wave trainfrequency may be anything suitable or desirable, and preferably of theorder of 500 or 1000 wave trains per second. The circuit of the coil Sis attuned by the condenser C to the current whose frequency correspondswith the wave train frequency of the distant transmitter. The coils daccordingly vibrate the armature j at corresponding frequency, throughthe member 0 vibration of the band F'at similar frequency; the band F,however, is preferably given a natural period corresponding with theWave train frequency, and accordingly, the amplitude of vibration of theband F builds up by resonance for a series or succession of transmittedwave trains.

In the absence of energizing current in the coils d, the contact an isin engagement with the band contact y, the pressure of the engagementdepending upon the strength of current through the exciting winding fand upon the strength of current in the exciting winding 1' of the twomagnet systems. In

the state of rest described, the force exerted upon the armature c bythe magnet system d preferably slightly preponderates over forcing theforce exerted on the armature by the magnet system 6 and accordingly thetwo contacts a: and 3 remain in engagement with each other, therebymaintaining the circuit of the windings i and j closed. The winding 9'being thus simultaneously energized, attracts the armature 0 against thestop '0 holding the circuit of the translating device T open inopposition to springg.

However, when the band F vibrates under the control of the receivedsignals, it periodically approaches and recedes from the contact at, andin attaining a predetermined magnitude of vibration under the influenceof the currents traversing the coil d, causes deflection of the yieldingcontact system, pendulum or lever z in counter-clockwise direction aboutits pivot (1 causing the armature 0 to approach the magnet system c andto depart from the magnet system d with the result that the magnetsystem 6 has now in effect obtained control. of the armature 0 holdingthe contact a: at some distance to the right of its normal positionindicated in Fig. 1. The natural period of vibration of the pendulumsystem a, c is long or great as compared with the period of vibration ofthe band F, and therefore the conta'ct a: does not return and promptlyfollow the band F, and such return of the contact 00 toward the band F,or any tendency to follow the band F, is retarded or reduced by themagnet system 6 When the band is vibrating as aforesaid, with thependulum system, .2, 0 deflected from its nor- I mal position asdescribed, the contact 1 periodically engages and separates from thecontact 02, thereby periodically interrupting the circuits of thewindings i and 7' the number of contacts or engagements between y and a:per unit of time corresponding with the frequency of the currenttraversing the coils d. The time constant of the circuit including thewinding 7' is great; that is, the ratio of inductance to resistance ishigh, whereby the current for each engagement of contact 3 with contact:1: cannot, before the next separation of contact y from contact aybuildup a magnitude suflicient to cause attraction of the armature 0Accordingly, while the member F is vibrating, the armature o is notattracted, and the circuit of. the instrument T remains closed.However,- when vibration of the member F ceases and the parts re-assumetheir position indicated in Fig, 1, the armature o is attracted andholds the circuit of the instrument T open.

The effect, therefore, of the periodic engagement and separation of-thecontacts y and a: is to convert, as regards the circuit of the winding9', a current of constant magnitude into a succession of currentimpulses of relatively far smaller amplitude, with \the result, asaforesaid, that the armature 0 is not attracted.

As aforesaid, the circuit of the winding 2' is periodically interruptedwhen the band F is vibrating, with the result that the magnetic field ofthe magnet system 6 periodically collapses, allowing the magnet systemal to exert relatively greater force upon the armature 0 thereby biasingthe contact w toward the left or normal position, as indicated in Fig.1.

The system a, 0 is made light, that is, of small mass and inertia, andof such small mass or inertia that lacking the magnetic controls al and6 the vibration of .the band F would cause the contact m to move arelatively great distance, I and a distance generally too great foroperative purposes.

It will therefore be understood that the pendular system 2, 0 while ofsmall inertia or mass, nevertheless has a natural period which is longcompared with the period enby tuning the coil S and condenser C to thefrequency of the wavetrains and therefore the frequency of the band F,electrodynamic braking of the band F is effected, whereby immediatelythe wave trains cease, the energy stored in the band F causes vibrationof the armature which, because of the permanent magnet h, then inducesin the circuit of the coils d a current of like frequency, and theproduction and dissipation of this current quickly dampens the band F,the damping effect being accentuated by the fact that the current isdelivered to the tuned circuit 8, C

Assuming that the distant transmitting apparatus emits continuous wavesor sus-. tained oscillations, each wave train may be broken up at thereceiving apparatus, as well understood in the art, by a so-calledtikker, chopper or equivalent, in which case the circuit S and C and theband F will be attuned to the frequency occasioned by thetikker, chopperor equivalent.

Or when the transmitting station emits that of the incoming energy. Asindicated,

the source H may be inductively related to the grid circuit ofthe'audion, as .by the oscillation transformer D. In this case, thecircuit 5, C and the band F are attuned to the beat frequency, as forexample, of the order of 500 or 1000 per second.

As indicated in Fig. 4, the pendular structure .2 may be suspended uponpoints 'w and may be provided with the weight m adj ustable to anysuitable position with respect to the points w to impart to the system adesired natural period. In this case, the magnet systems e and d of Fig.1 are omitted, and there will be in the circuit of the contacts 00, 3/the winding 7' of the magnet system n only;

In Fig. 5, the contact m is secured upon a spring or reed 3 secured tothe abutment 2 In this instance the contacts a: and y will control onlya relay, as 1?), the circuit of whose winding j will be controlled bythe relay contacts. In this instance, the natural period of the reed orspring 11 may be long or short as compared with the natural period ofthe band F, and in any event, need not be attuned to the same frequencyas the band F.

In accordance with the modification indi cated in Fig. 6, the contact mis carried by a reed or vibratory member a, secured to the abutment band preferably being attuned, as is also the. band F, to the frequencyof the current traversing the two pairs of coils d, one pair energizingthe band F and the second pair energizing or operating the reed 411?,both pairs of coils (1 receiving their current from the tuned circuit SC as in Fig. 1. The direction of winding of sense-of connections of thedifferent pairs of coils d is such that when the band F is driven towardthe left, for example, the contact m is driven toward the right. Inother words, the two resonantelements F and a are driven in oppositesenses. In this case again, as in the case of Figs. 1

and 5, electro-dynamic braking is effected by the generation in thecoils d of current representative of the vibratory energy in the memberF or members F and (1 In the examples above illustrated and described,the control of the local circuit, as that of the winding is sharp andclearly defined, because responsive only to currents of frequencycorresponding with the frequency of the band F. Accordingly, the effectsof atmospheric electricity, static, strays, etc., are reduced to aminimum, without blurring or uncertainty or irregularity in closure andopening of the circuit of the winding j. Similarly, Wave trains ofundesired frequency are not responded to, and in the case of employmentof heterodyne reception, the frequency of the current traversing thecoil (5 may be chosen at will, and the, band F, Figs. 1 and 5, and bandF and reed a, Fig. 6, may be correspondingly tuned.

By utilization of the method and apparatus as herein described, and moreparticularly by utilization of apparatus of the character indicated inFig. 1, I have been able, when static, strays and-other atmosphericdisturbances were. great, to produce a telegraphic record upon a tape,as when the instrument T was a tape recorder, whose code characters weredecidedly sharp and senting current damping one of said con-.

tacts.

2. The method of receiving electrical signal energy by means of acircuit controlled by co-acting contacts normally in engagement witheach other, which comprises vibrating one of the contacts under controlof said current at a frequency corresponding with the frequency of saidcurrent to deflect another of said contacts and to periodically open andclose said circuit, translatinginto intelligible signals the effects ofthe periodic opening and closure of said circuit and upon cessation ofsignal-representing current electro-dynamically damping one of saidcontacts.

3. The method of receiving electrical signal energy by meansof a circuitcontrolled by co-acting contacts one of which is biased toward theother, which comprises vibrating another of said contacts under controlof said current at a frequency corresponding with the frequency of saidcurrent to deflect said one of said contacts and to periodically openand close said circuit, periodically varying the bias upon said one ofsaid contacts by said periodic opening and closing of said circuit, andtranslating into intelligible signals the effects of the periodicopening and closure; of said circuit. 4. The method of receivingelectrical signal ener by means of a circuit controlled byco-actmgcontacts, which comprises vibrating under control of saidcurrent a member having a natural eriod corresponding with the period ofsald current, vibrating one of said contacts by said vibrating member toperiodically open and close said circuit, translating into intelligiblesignals the effect of the periodic opening and closure of said circuit,and upon cessation of signalrepresenting energy damping said vibratingmember.

5. The method of receiving electrical signal energy by means of acircuit controlled by co-acting contacts normally in engagement witheach other, which comprises vibrating under control of said current amember having a natural period corresponding with the period of saidcurrent, vibrating one of said contacts by said vibrating member todeflect another of said contacts .to periodically open and close saidcircuit, translating into intelligible signals the effects of theperiodic opening and closure of said circuit, upon cessation ofsignal-representing energy damping said vibrating member byelectro-dynamically generating a current thereby, and dissipating saidcurrent in a circuit tuned to said last named current.

6. The method of receiving electrical signal energy by means of acircuit controlled by co-acting contacts one of which is biased towardthe other, which comprises vibrating under control of said current amember having a natural period corresponding with the period of saidcurrent, vibrating another of said contacts by said vibrating member todeflect said one of said contacts and to periodically open and 'closesaid circuit, periodically var ing the bias upon said one of saidcontacts y said periodic opening and closing of said circuit, and transating into intelligible si als the efiects of the periodic opening and cosure of said circuit.

7. The method of receiving telegraphic signals represented intransmission by electro-radiant energy with reduction of the ef iects ofelectrical disturbances, as static, strays, atmospherics, etc., by meansof a circuit controlled by co-acting contacts one of which is vibratoryand another of which is capable of deflection, which comprises produoina periodic current representative of the te egraphic signals, vibratingunder control of said current a member having a natural periodcorresponding with the period of said current, vibrating said vibratorycontact by said member and deflecting said other contact to periodicallyopen and close said circuit, and translating into intelligible signalsthe efiects of the periodic opening and closure of said circuit.

8. An anti-static system for reception of radio telegraphic signalscomprising means for producing a periodic current representative of thetelegraphic signals, a circuit a translating instrument controlledthereb co-operating. contacts controlling said clrcuit, means forvibrating one of said contacts at a frequency corresponding with thefrequency of said current to riodicall open an close said circuit, anmeans e fective upon cessation of signal-representing one for dampingone of said contacts.

9%23 combination with a source of periodic current, of a circuit, atranslating instrument controlled thereby, a vibratory contact and asecond contact controlling said circuit, means biasing said secondcontact toward said vibratory contact, and means for vibrating saidvibratory contact at a frequency correspondlng with the frequency ofsaid current to periodically open and close said circuit.

10. The combination with a source of periodic current, of a circuit, atranslating instrument controlled thereby, a vibratory contact and asecond contact controlling said periodic current, of a circuit, atranslating Instrument controlled thereby, a vibratory contact and asecond contact controlling said circuit, means continuously biasing saidsecond contact toward said vibratory contact, means for vibrating saidvibratory contact at a frequency corresponding with the frequency ofsaid current to periodically open and close said circuit, and a secondbiasing means controlled by said contacts and periodically opposing saidfirst named biasin means.

12. he combination with a source of periodic current, of a circuit, atranslating instrument controlled thereby, a vibratory contact and asecond contact controlling said circuit, and a member vibrated undercontrol of said current and having a natural period corresponding withthe period of said current, said vibratory contact vibrated bysaidmember to periodically engage and separate from said second contact andthereby periodically open and close said circuit.

13. The combination with a source of pe-' riodic current, of a circuit,a translating mstrument controlled thereby, -a vibratory contact and asecond contact controlling said circuit, a member vibrated under controlof said current and having anatural riod corresponding with the periodof sai current, said vibratory contact vibrated b said member, and meansbiasing said secon con-" tact toward said vibrato contact.

14. The combination with a source of poriodic current, of a circuit, atranslating instrument controlled thereby, a vibrato contact and asecond contact controlling sai circuit, a member vibrated undercontrolof said current and having a natural riod corresponding with theperiod of sai current, said vibratory contact vibrated by said member,and 'means continuously biasing saidvsecond contact toward saidvibratory contact. I

15. The combination with a source of-periodic current, of a circuit, atranslating instrument controlled thereby, a vibratory contact and asecond contact controlling said circuit, 'a member vibrated undercontrol of said current and having a natural riod corresponding with the'period of sai current, said vibratory-contact vibrated by said member,means continuously biasing said second contact toward said vibratorycontact, and a second biasing means controlled by said contacts.

16. The'combination with a source of periodic current, of a circuit, atranslatmg instrument controlled thereby, a vibratory contact and asecond contact controlling said circuit, a member vibrated under controlof said current and having a natural eriod corresponding with the periodof sai current, said vibratory contact vibrated by said member, meanscontinuously biasing said second contact toward said vibratory contact,and a second biasing means opposing said first named biasing means andcon trolled by said contacts.

17. The combination with a circuit, of a translating instrumentcontrolled thereby, a vibratory contact and a second-contact controlling said circuit, and means for damping said vibratory contact.

18. The combination with a circuit, of a translating instrumentcontrolled thereby,

a vibratory contact and a second contact con-' trolling said circuit,and means moving with said vibratory contact for generatlng a dampingcurrent.

19. The combination with a circuit, of a translating instrumentcontrolled thereby, a vibratory contact and a second contact controllingsaid circuit, a circuit resonant to a frequency correspondin with thefrequency of vibration of said vi ratory contact, and means movable withsaid vibratory contact for producing in said resonant circuit a dampingcurrent.

20. An anti-static system for reception of radio telegraphic signalscomprising means for producing a periodic current representative of thetelegraphic signals, a circuit, a telegraphic recorder controlledthereby, cooperating contacts controlling said 'clrcuit, means forvibrating one of said contacts at a frequency corresponding with thefrequency of said current to periodically open and close said circuit,and means operative upon cessation of signal-representing energy fordamping one of said contacts.

In testimony whereof I have hereunto afiixed my signature this 12th dayof March,

DAVID G. MoCA A.

